1. Field of the Invention
The present invention relates to a nucleic acid detection cassette which completely automatically performs the detection of a nucleic acid and its pretreatment step for a purpose of detecting a target nucleic acid, and a nucleic acid detection device by use of this nucleic acid detection cassette.
2. Description of the Related Art
In recent years, with development of genetic engineering, it becomes possible to diagnose or prevent a disease by a gene in a medical field. This is called genetic diagnosis. A human genetic defect or change as a cause for the disease can be detected to diagnose or predict the disease before it is developed or in a remarkably initial stage of the disease. With deciphering of a human genome, an investigation on a genotype and a plague has been proceeded, and diagnoses (tailor-made diagnoses) have been actualized in accordance with individuals' genotypes. Therefore, it is very important to easily detect the gene and determine the genotype.
Heretofore, to detect a nucleic acid, there have been used various devices such as a nucleic acid extraction device, a nucleic acid amplification device, a hybridization device, a nucleic acid detection device, and a data analysis device. Moreover, manpower has been required in preparation of samples and movement of the samples between the devices which are operations other than operations realized by these devices.
A PCR method is mainly used in amplifying the nucleic acid. This method has a very high amplification factor. Therefore, there is a problem that when even a remarkably slight amount of another nucleic acid is mixed into the sample before amplified, even the nucleic acid is amplified into a large amount, and erroneous detection is caused. It is known that nucleic acid molecules are stabilized even in dried states, the molecules are adsorbed by various substances, and the molecules sometimes float in the air. Therefore, to prevent the erroneous detection, a severe administrative system is required in which the amplified sample is not brought into a place where the nucleic acid is extracted.
In recent years, there is developed a device which automatically performs steps of hybridization reaction to data analysis. Recently, there is also developed a fully automatic nucleic acid detection device which automatically performs the extraction of the nucleic acid to the data analysis. However, in the existing fully automatic nucleic acid detection device, any secure measure is not taken against mixture of a nucleic acid molecule which is not an object of the detection. Moreover, since the device is often large scaled, it is aimed at an investigation application. For example, Jpn. Pat. Appln. KOKAI Publication No. 3-7571 discloses a nucleic acid detection device which amplifies and detects the nucleic acid and which can handle automatic processing.
Important problems in the development of the fully automatic nucleic acid analysis device are the mixture of the nucleic acid molecule which is not the object of the detection from the outside and leaking of the nucleic acid sample to the outside.